4 ways the police gather evidence during DUI traffic stops

On Behalf of | Nov 20, 2023 | DUI |

Many drivers have never been stopped by the police. The first time it happens can be startling. Unfortunately, doing the wrong thing at that moment could make the situation worse and put you in legal jeopardy.

Drivers need to learn what happens during a traffic stop and how the police gather evidence when they’re suspicious that you’re impaired. Here’s what you should know:

Reasonable suspicion and probable cause are different things

Before the police have the right to stop a vehicle, they must have reasonable suspicion that a driver is violating the law. For example, seeing a driver swerving between lanes could give an officer reasonable suspicion that the driver is impaired. That’s enough to justify a traffic stop.

If the police notice that a driver has an open bottle of alcohol in their vehicle, however, then they may have probable cause. Probable cause is sufficient reasoning based on facts to conduct an investigation or arrest. 

Officers frequently use investigative questioning techniques to get information

The police often ask drivers several questions during traffic stops. This may include asking where the driver has been or if the driver has been drinking. Drivers can answer these questions, but even drivers who have not been drinking may make a self-incriminating comment that can lead to an arrest. People have the right to plead the Fifth if they do not want to answer questions. 

Standardized field sobriety tests are used to bolster probable cause

If the police do not gather enough evidence from the first two methods, they may ask drivers to perform a standardized field sobriety test (SFST). An SFST can include a horizontal gaze nystagmus test, walk-and-turn test or a one-legged stand test. These tests are physical examinations that might help the police spot signs of inebriation. They’re primarily tools to give the police enough probable cause for an arrest.

Chemical sobriety tests are used to confirm suspicions

While SFSTs can produce results, they are not always accurate. The police can ask drivers to take chemical sobriety tests that evaluate the blood alcohol content (BAC) in the body. While drivers can take urine and blood tests, the most common evaluation is a breath test. Breath tests are so common because they can be done during a traffic stop while the other tests may require the driver to relocate to a hospital. These are typically conducted after an arrest and used to confirm an officer’s suspicions.

It can help drivers to understand what happens during a traffic stop and what their legal rights are. If a driver believes their legal rights were violated, they may seek defense options.